Plants and plant hormones
- Created by: Emma Redding
- Created on: 22-04-13 19:44
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- PLANTS
- TROPISMS
- There are four main types of tropisms:
- Phototropism is when shoots grow towards the light which enables them to photosynthesise.
- Chemotropism is when the pollen tubes on a flower grow down towards the ovary where fertilisation takes place.
- Thigmotropism is where shoots of climbing plants wind around other plants or solid structures for support.
- Geotropism is where roots grow towards the pull of gravity to anchor them in to the soil and take up water.
- A directional growth response in which the direction of the response is determined by the direction of the external stimulus.
- There are four main types of tropisms:
- HORMONES
- Auxins
- Promote cell elongation; inhibit growth of side shoots; inhibit leaf abscission.
- Gibberellins
- Promote seed germination and growth of stems.
- Cytokinins
- Promote cell division.
- Ethene
- Promotes fruit ripening.
- Abscisic Acid
- Inhibits seed germination and growthy; causes stomatal closure when there is low water availability.
- Auxins
- MERISTEMS
- Apical
- Found at the tips or apices of roots or shoots- responsible for growth of these areas.
- Lateral Bud
- Found in the buds. Could give rise to side shoots.
- Lateral
- Found in a cylinder near the outside of roots and shoots and are responsible for these getting wider.
- Intercalary
- Located between nodes. Growth between nodes are responsible for the shoots getting longer.
- Apical
- TROPISMS
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